Multiple ip on an interface with netplan

Question

I have a server that uses multiple ip for proxies with Squid.

I'm setting it up on a new server, but with Ubuntu 18 I need to rewrite /etc/network/interfaces for netplan.

On the old server /etc/network/interfaces is like this:

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
    address 1.2.3.4
    netmask 255.255.255.0
    network 1.2.3.0
    broadcast 1.2.3.255
    gateway 1.2.3.254

auto eth0:0
iface eth0:0 inet static
        address 5.6.7.8
        netmask 255.255.255.255
        broadcast 5.6.7.8

It has eth0:1, eth0:2, etc.

Which gives this in ifconfig -a:

eth0      Link encap:Ethernet  HWaddr 0c:c4:7a:79:37:54
          inet addr:1.2.3.4  Bcast:1.2.3.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:3149890977 errors:0 dropped:0 overruns:0 frame:0
          TX packets:6290843324 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1281967559959 (1.2 TB)  TX bytes:7746334018193 (7.7 TB)

eth0:0    Link encap:Ethernet  HWaddr 0c:c4:7a:79:37:54
          inet addr:5.6.7.8  Bcast:5.6.7.8  Mask:255.255.255.255
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

I tried rewriting it different ways in /etc/netplan/conf.yaml, for example like this:

network:
  version: 2
  renderer: networkd
  ethernets:
    prox:
      addresses:
        - 1.2.3.4/24
        - 5.6.7.8/32
      gateway4: 1.2.3.254

then run "netplan try" but only 1.2.3.4 appears in ifconfig.

ip -4 addr list shows:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
4: eno3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    inet 1.2.3.4/24 brd 1.2.3.255 scope global eno3
       valid_lft forever preferred_lft forever

Solution

Your netplan config refers to an interface prox, which doesn't exist on your system.

Replace it with eno3 - the actual interface name on the system - and then reapply your netplan configs.

Comments

[Thomas Ward]

Is prox an actual interface name? It looks like the interface name you need to use in your yaml is eno3... Try adjusting the yaml config to use eno3 instead of prox and try again.

[leyou]

Annnnnnd... I feel stupid. Thank you for the help.